A network of computers or other devices can span a variety of distances. One type of network, a wide area network (WAN), connects networked devices across great distances, perhaps in different cities or even in different countries. An example of a WAN is the Internet. Another type of network, a local area network (LAN), connects devices within a building or a campus of buildings, for example.
Yet another type of network, a personal area network (PAN), connects networked devices across relatively short distances. A PAN may connect devices within an area the size of a single room of a building or bigger, or perhaps a smaller area such as a few feet or meters. As an example, a PAN may consist of a computer networked with a printer and a scanner. A PAN may even connect devices worn on a person. For example, a PAN may consist of a mobile phone (perhaps in jacket pocket) networked with a wireless headset (likely worn on the person's ear).
Any device can be a PAN device so long as it is able to communicate with other devices that are in relatively close proximity to the PAN device. In addition to the devices mentioned above, MP3 players and personal digital assistants can be PAN devices. Even devices not conventionally thought of as networked devices can be PAN devices. For instance, an automobile can be a PAN device, and even a pair of eyeglasses can be PAN device, if these devices are configured to communicate over short distances with other PAN devices.
PAN devices can communicate with other PAN devices wirelessly and/or over a wired network, and to facilitate this communication, several PAN protocols have been developed. Examples of wired PAN protocols include Universal Serial Bus (USB) and FireWire, and examples of wireless PAN protocols include Bluetooth and ZigBee. The Bluetooth protocol is a widely implemented PAN protocol, and is used by numerous mobile PAN devices, including mobile phones, wireless headsets, personal digital assistants, and MP3 players. For example, Bluetooth is commonly used to network a mobile phone and a wireless headset. Wireless headsets that implement Bluetooth are often referred to as Bluetooth headsets.